Various techniques have been proposed for layered structures and membranes. For example, Winnick, J., Marshall, R., and Schubert, F., “An Electrochemical Device for Carbon Dioxide Concentration. I. System Design and Performance,” Ind. Eng. Chem., Process Des. Develop., Vol. 13, No. 1, 1974, pp. 59-62, describes the use of electrochemical cells for carbon dioxide concentration. These and similar methods use electrochemical or “polarization membranes.” These membranes operate on the principle that CO2 is converted to soluble carbonates and bicarbonates at high pH and is liberated again at low pH. CO2 is preferentially absorbed on the basic side and released on the acidic side.
U.S. Pat. No. 5,773,645 describes two-dimensional electrophoresis devices that include strip gels and slab gels, isolated from each other by a removable, fluid-impermeable and electrically insulating barrier. A strip containing immobilized groups and a solid or gel matrix can be used; for example, a strip of dry immobilized pH gradient gel is described. Various positively or negatively charged groups are described.
It would be advantageous to have improved techniques relating to layered structures and membranes.